For what it's worth... here is my 2 cents.
I'm 43, been riding off and on since I was a teenager. 1st street bike was an older suzuki gs450, learned to ride that thing in LA traffic to boot.
from there I went to a GS 850, had a yamaha 750, and a goldwing 1200 (no fairings).
A year and a half ago i ended up buying a yamaha roadstar warrior, I'm 6'2" and 180lbs, like you, the bike felt heavy under me and very hard to control. The power is wicked on this thing as with the M109. It scared the hell out of me.
Now, after a year and a half, I am more use to the bike and want to do more. I found out that these things will wheelie... that is where I am.
IMO, it's better to grow into a bike than out of one. However, unless you are willing to take the bumps should something happen, start a bit smaller. When I first got the bike, had an incident, not all my fault, there was a recall on the bike and the bike stalled in a turn. To avoid traffic I headed off the road, hit some soft dirt and laid it down. If I had been a little more experienced with the bike, I might have avoided that.
Best advice I can give you is to get a bike that FEELS right to you. If you are having a hard time controlling it standing still, just imagine what that will be like when you are in motion.
What ever you get, take it easy and be safe
